The present invention relates to the field of mass storage devices. More particularly, this invention relates to a drive test fixture for testing or assembling a disc drive.
One key component of any computer system is a device to store data. Computer systems have many different places where data can be stored. One common place for storing massive amounts of data in a computer system is on a disc drive. The most basic parts of a disc drive are a disc that is rotated, an actuator that moves a transducer to various locations over the disc, and electrical circuitry that is used to write and read data to and from the disc. The disc drive also includes circuitry for encoding data so that it can be successfully retrieved and written to the disc surface. A microprocessor controls most of the operations of the disc drive as well as passing the data back to the requesting computer and taking data from a requesting computer for storing to the disc.
The transducer is typically placed on a small ceramic block, also referred to as a slider, that is aerodynamically designed so that it flies over the disc. The slider is passed over the disc in a transducing relationship with the disc. Most sliders have an air-bearing surface (xe2x80x9cABSxe2x80x9d) which includes rails and a cavity between the rails. When the disc rotates, air is dragged between the rails and the disc surface causing pressure, which forces the head away from the disc. At the same time, the air rushing past the cavity or depression in the air bearing surface produces a negative pressure area. The negative pressure or suction counteracts the pressure produced at the rails. The slider is also attached to a load spring which produces a force on the slider directed toward the disc surface. The various forces equilibrate so the slider flies over the surface of the disc at a particular desired fly height. The fly height is the distance between the disc surface and the transducing head, which is typically the thickness of the air lubrication film. This film eliminates the friction and resulting wear that would occur if the transducing head and disc were in mechanical contact during disc rotation. In some disc drives, the slider passes through a layer of lubricant rather than flying over the surface of the disc.
Information representative of data is stored on the surface of the storage disc. Disc drive systems read and write information stored on tracks on storage discs. Transducers, in the form of read/write heads attached to the sliders, located on both sides of the storage disc, read and write information on the storage discs when the transducers are accurately positioned over one of the designated tracks on the surface of the storage disc. The transducer is also said to be moved to a target track. As the storage disc spins and the read/write head is accurately positioned above a target track, the read/write head can store data onto a track by writing information representative of data onto the storage disc. Similarly, reading data on a storage disc is accomplished by positioning the read/write head above a target track and reading the stored material on the storage disc. To write on or read from different tracks, the read/write head is moved radially across the tracks to a selected target track. The data is divided or grouped together on the tracks. In some disc drives, the tracks are a multiplicity of concentric circular tracks. In other disc drives, a continuous spiral is one track on one side of a disc drive. Servo feedback information is used to accurately locate the transducer. The actuator assembly is moved to the required position and held very accurately during a read or write operation using the servo information.
Many of these parts are easily damaged particularly when the disc drives are being assembled or tested. Existing assembly and testing methods include hand assembly of drives. Drive covers may be attached and aligned to the drive bases by using hand-eye coordination. The drive covers may include PCBA (Printed Circuit Board Assembly) connectors. In order to meet productivity goals, assemblers may inadvertently slip or misjudge the location of the parts to be assembled, causing inadvertent contact of sensitive parts resulting in damage and excessive defects. In order to prevent such damage, assemblers may be very deliberate and slow, decreasing productivity. In addition, if the tolerances are close, such as with aligning the male and female ends of a PCBA connection, aligning the parts may be difficult to accomplish by hand.
What is needed is a disc drive test fixture that eases alignment, improves productivity, and reduces damage and cost.
The present invention is a drive test fixture and method which provides ease of alignment, improved productivity with reduced damage and cost. In accordance with one embodiment of the invention, a drive fixture is provided including a base, a stop guard, a pair of guide rails, and a cradle. The stop guard and the guide rails may be located on the base for positioning a cover against the stop guard and between the guide rails. The stop guard, the guide rails, and the cradle may be located so that one end of the cover may be pivoted at the stop guard as the other end is lowered between the cradle and the guide rails. The guide rails may have a width and a height so that a misaligned cover contacts the top edge of at least one of the guard rails before contacting the base of the disc drive. The guide rails may have chamfered edges. The pair of guide rails may be parallel to each other and have an adjustable width of separation. The base may have slotted openings for adjusting the guide rails by fastening the guide rails through the slotted openings. The stop guard may have a slot or may be C-shaped for positioning the cover. The drive fixture may also include dowel pins for removably attaching the cradle to the base, with the base having dowel bores for receiving the dowel pins and the cradle having dowel slots for receiving the dowel pins. The cradle may have a recess opening for receiving the base of the disc drive.
Also disclosed is a method for assembling a cover of a disc drive to a base of a disc drive. The method includes the steps of providing a drive fixture having a stop guard and a pair of guide rails, positioning the cover against the stop guard, lowering the cover between the pair of guide rails and over the base of the disc drive, and fastening the cover of the disc drive to the base of the disc drive. Positioning the cover against the stop guard may also include pivoting one end of the cover at the stop guard and lowering the other end of the cover between the guard rails and the base of the disc drive with the guard rails protecting the base of the disc drive from damage by the cover. The cover and base of the disc drive may also include a PCBA connector with a male and female end. The PCBA connector ends may also be aligned, connected and protected. Providing a drive fixture may also include providing a pair of guard rails dimensioned so that a misaligned cover contacts the top of at least one of the guide rails before contacting the base of the disc drive. Providing a drive fixture may also include providing a cradle. Lowering the cover between the guide rails and over the base of the disc drive may include lowering the cover between the pair of guide rails and the cradle. The method may also include moving the cover away from the stop guard and parallel to the pair of guide rails for positioning the cover for attachment to the base of the disc drive, prior to fastening the cover of the disc drive to the base of the disc drive. The method may also include moving the cover away from the stop guard and parallel to the pair of guide rails for positioning the male and female ends of a connector, prior to fastening the cover of the disc drive to the base of the disc drive. The method may also include fastening additional parts to the disc drive.
The invention also discloses a drive fixture including a holding means for holding a base for a disc drive, and a positioning means for positioning a cover for the disc drive for attachment to the base for the disc drive.
Advantageously, the present invention provides ease of alignment, and improved productivity with reduced damage and cost. The drive fixture provides a device and method for easily aligning drive covers for attachment to drive bases. The present invention aligns the parts without the need of good hand-eye coordination. The stop guard and guide rails align the cover onto the base with minimal effort. In addition, the present invention allows the assembly of disk drives without the worry of damaging the disc drives or connectors by inadvertently slipping or misjudging the location of parts, increasing productivity and reducing damage.